Rotary piston pump



June 8, 1965 w. STIEBER ROTARY PISTON PUMP 3 Sheets-Sheet 1 Filed NOV. 5, 1962 11 IIIIIIIl/I', r2 ,7 8

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June 8, 1965 w. STIEBER 3,187,677

ROTARY PISTON PUMP Filed Nov. 5, 1962 3 Sheets-Sheet 2 FIG. 4

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,4 7' mRNE K United States Patent 0 3,187 ,67 7 ROTARY PESTON Elm l? Wilheim Stieber, 2i) Spitaistrasse, Weingarten, Wurttemberg, Germany Filed Nov. 5, 1962, Ser. No. 235,220 11 Claims. (U. 103-12d) The present invention relates to a rotary pistonpump and more particularly to a rotary piston pump affording infinitely variable output between a minimal output and a maximal output. 7

In conventional rotary piston pumps of this type infinite variability of the output is obtained by radial rela tive displacement of elements having circular surfaces, such as rotary pistons and rings, which define suction and pressure chambers.

The conventional arrangements cause one-sided liquid pressures which act on the entire cross section of the space enclosed by the outer element and cause relatively great bearing loads, reducing the operating pressure and the output.

Rotary piston pumps are known wherein the stroke volume is changed by moving circle-segment-shaped elements. This involves paths having curvature changes which are not continuous and cause shocks.

It is an object of the invention to provide a rotary pump which avoids the disadvantages of conventional rotary pumps andwhich, particularly, avoids all bearing pressures and substantially avoids friction losses so that an overall etliciency is obtained which exceeds that of conventional rotary pumps.

The pump according to the invention is symmetric at all output conditions and all forces acting in the pump are counterbalanced. Only the weight of the rotary acts on the bearings so that friction losses are greatly reduced and the overall efficiency is improved. The pump according to the invention can be built at reduced cost compared with the cost of conventional pumps affording infinite variability of output.

The pump according to the invention includes a conventional rotor provided with a number of vane devices which are free to slide radially in the rotor. The vane devices bear against an elastically deformable annular element surrounding the rotor and confining a space therearound which is divided by the vane devices into suction and pressure chambers. This deformable annular element is coaxial of the rotor and within the pump casing and can be deformed to change its curvature and to change the configuration of the suction and pressure chambers to suit variable loads. Elastic deformation of the annular element may be effected by mechanical means controllable from the outside of the pump casing or by difierent and adjustable hydraulic or pneumatic pressures acting on difierent portions of the outside of the annular.

element.

In a modification of the pump according to the invention the rotor is not solid but annular and the vane devices slidably extend radially through the piston, i.e. are adapted to project from the inside as well as from the outside or" the annular piston. An elastically deformable annular element is provided outside and is coaxial with and surrounds the piston. A second elastically deformable annular element is provided inside and coaxial with the piston. Both annular elements are abutted by the vane devices and the configuration or curvature of the 3,187,677 Fatented June 8, 1965 I pump shown in FIG. 1.

inner element is changed by the vane devices correspondtwo pumps are obtained which may be arranged in series or in parallel relation with respect to the flow of the FIG. 3 is an illustration of a modified systemrfor adjusting the curvature of elastically deformable annular elements forming part of thepump according to the invention.

FIG. 4 is a part-sectional side view of the pump shown in FIG. 1.

FIG. 5 is a diagrammatic cross-sectional view of a modified rotary piston pump having a solid rotary piston.

PEG. 6 is a diagrammatic cross-sectional view of a further modification of a rotary piston pump wherein the mounting and deformation of the annular elements are efiected by the same elements.

FIG. 7 illustrates a modified construction of the mountring shown in FIG. 6. 7

FIGS. 8 and 9 show two types of roller chains for guiding rollers of anti-friction support means forming part of the pump shown in FIGURES 1 and 4.

In the pump shown in FIGURES 1 and 4 an annular rotary piston 22 is mounted concentrically to a drive shaft 1 in a casing 11 having covers 42 and 43, and carries in radially symmetrical slots five movable vane devices 3, 4.

Each slide consists of two vane device plates 3 between which an even number of rollers 4, in the illustrated example two rollers, are disposed in parallel relation. The slide plates 3 may have grooves wherein the rollers 4 are rotatable. In some cases the use of slide plates 3 can be avoided, the rollers '4 sliding with a suitable fit in the slots in the rotary piston 2.

The length of the vane devices 3, t in the radial direction is greater than the thickness of the annular rotary piston 2. Therefore, the vane devices project outward and inward from the rotary piston.

The width of the vane devices in the peripheral direction is determined by the diameter of the rollers 4 and the thickness of the two slide plates 3. The width of the vane devices in the peripheral direction can be such that the tipping moment of the vane devices at the change of pressure is reduced or eliminated.

The rollers 4 at the inside of the vane devices bear against an elastic annular element 5 which presses aaginst the said rollers. The outer rollers 4 rest on an elastic annular element 6, which with anti-friction elements 7 and an elastic annular element 8, forms an anti-friction bearing. The elements 5 and 6 are of such dimensions that they exert a predetermined pressure on the rollers 4. This effects a-force connection and sealing of these parts in relation to one another.

The annular space between the inside of the element 5 and the outside of the element 6 is closed on both sides in the axial direction by corresponding cover rings 36 and 37 (FIG. 4). number of which is twice the number ofrvane devices and which are offset in relation to one another at equal distances.

The cover ring 37 is provided with a channelfor each pump chamber, channels 38 and 39-being visibleand the other channels being not visible in FIG; 4. These channels are suitably distributed on the coverlring so that supply and discharge of operating medium to and from channels 34 and 35 provided in a stationary valve This forms stroke spaces, the

element 33, arranged around the shaft 1, take place in the proper sequence.

In pumps of relatively great capacity a cover ring similar to the ring 37 and a cover similar to the cover 42 may also be provided on the left side of the pump in lieu of the cover ring 36 and the cover 43 of the example shown in FIG. 4. y

The axial lengths of the elements 3, 4, and 6 are. equal. They are a little shorter than the axial distance, between the cover rings 36 and 37 to provide a clearance affording free relative movement.

The cover rings 36 and 37 are rigidly connected to the rotary piston-2 and, by means of a key 32, to the shaft 1. The aforesaid parts form a rotor.

The outer annular element 8 of the pump shown in FIGS. land 4 is movable relative to the stationary covers'42 and 43. The element 8' is held coaxial of the shaft 1 by means of axial ledges 12 and sealing elements 13 received in axial grooves of said ledges.

The annular elements 5,6 and 8 are made of highly elastic material and are of such dimensions as to permit substantial elastic deformation. These elements may be made upof a plurality of concentric, elastic and adjacentannular elements. Element 5 is so shown in FIGS. 1 and 4.

The rotor, the annular elementS and the elements 6, 7, 8 which form an antifriction bearing are inserted in a casing 11 on the inside of which the four internal axial ridges or ledges 12 are radially symmetrically arranged. Each ridge is provided with a groove extend ing in axial direction for receiving a sealing element 13. Due to its excessive circumferential length the annular element 8 is pressed against the elements 13 and/or the ridges 12. The elements 8 and 13,-the casing 11 and the covers 42 and 43 define four spaces 18 to 21. The spaces 18 to 21 are individually connected with the outside by apertures 14 to 17, respectively, in the casing 11.

Operation Ifthe shaft 1-is rotated, the aforedescribed rotor runs vided between the cover 43 and the cover ring 36 and between the cover 42 and the cover ring 37, respectively, without appreciable resistance and without transporting fluid.

If a liquid or gaseous pressure fluid is supplied into the spaces 18 and 19 through the apertures 14 and 15, the annular elements 8, 6 and 5 are elastically deformed to assume oval configurations.

This deformation of the elements 5 and 6 produces pressure and suction chambers confined by the rotary piston 2, the vane devices 3, 4 and the annular elements 5 and 6. The stroke of the pump is proportional to the difference between the principal axes of the ovals. The stroke isalso proportional to the pressure of the fluid which is introduced through the apertures 14 and 15. The stroke volume and the output of the pump are proportional to the stroke. 7

If the pressure fluid is relieved from the spaces 18,

and 19 and pressure fluid is introduced into the spaces 20 and 21 through the apertures 16 and 17, the pump operates in the opposite direction.

FIG. 2 illustrates a modified positioning device for the annular element 8 in FIG. 1 or the annular element 6 in FIG. 5. In this case pins or rollers 25 are placed in suitable recesses of the ledges 12 and of support shoes 24 abutting against the outside of the annular element 8 or 6. The pins 25 and shoes 24- may be as long as the axial interior length of the casing 11. The shoes 24 may be provided with axial recesses 23 facingthe annular element 8 or 6 for improving engagement when" the annular element is deformed. The pins 25 may be rigidly connected either to the ledges 12 or to' the shoes 24.

FIG. 3 illustrates a modified support of the annular element 8 of the pump shown in FIG. 1. The element is held in a position coaxial of the rotation axis of the rotor by means of rollers 29 which are radially symmetrically arranged in the casing 11. Deformation of the annular element is effected by means of roller pairs 28 supported by suitable jacks 27 which can be actuated from the outside of the casing 11 whereby the forces P and P acting on diametrically opposed jacks are equal.

The example of a pump according to the invention shown in FIG. 5 comprises a casing 46 provided with internally projecting radially symmetrically arranged axial ledges 47 to 54), each ledge having an axial groove containing a sealing element 67. Two adjacent elastically deformable annular elements 6 are inserted in the casing 46 and placed around a rotor 57. ,The elements 6 are held in coaxial position with the pump shaft 1 by the ledges ,47 to 50. Because of the excessive length of the annular elements they exert pressure against the ledges 47 to 50 and/or the sealing elements 67. The elements 6, the ledges 47 to 50 and end covers of the pump form four chambers 53 to 56. The rotary piston 57 is solid and supported by the shaft 1 inside and coaxial of the annular element 6. The piston 57 is provided with slide plates 58 in the conventional manner.

The annular elements 6 may be elastically deformed by means of shoes 59 to 62 which are pairwise arranged in diametrically opposite positions and are pressed by equal forces P and P in diametrically opposed directions. The forces applied to one pair of shoes are different from the forces applied to another pair of shoes. The shoes applying different forces may be actuated by a two-arm lever 69 swinging on a fulcrum 7t). Alternatively, the annular elements 6 may be deformed pneumatically or hydraulically by introducing a fluid of suit able pressure into the chambers 53 to 56.

FIG. 6 is a diagrammatic cross-sectional view of a further modification of a pump according to the invention. Three jacks are provided inside a casing 76, each jack swingably supporting at 81 a two-arm lever 82. A shoe 33 is swingably mounted on the end of each arm of each lever 82. A concentrically placed elastic annular element 6 presses against the shoes 83. The levers 82 are interconnected by means not shown, for uniform simultaneous swinging about the fulcrums 31. If the levers 82 are turned through like angles, the annular element 6 is symmetrically deformed to assume a triangular shape. With the arrangement according to FIG. 6 no special supports for the annular element 6 within the casing 76 are required. The aforedescribed deformation produces stroke spaces. Each stroke space situated between two slide plates 58' of a conventional pump rotor draws and discharges fluid three times during one revolution of the rotor 57, 58. Therefore, the pump having seven slide plates 58 discharges twenty-one times during one revolution.

Instead of the twofold deformation of the annular element 6 in the pumps shown in FIGURES 1 and 5, respectively, and instead of the threefold deformation of the annular element 6 of the pump shown in FIG. 6, fourfold or even higher deformation may be effected.

The elastic annular elements which are in the form of short tubes may be composed of a plurality of short tubes placed one within the other. This is shown with respect to the element 5 in FIG. 1 and to the element 6 in FIG. 5.

In the embodiment of the invention shown in FIG. 6 the shoes 83 may be replaced by rollers 85 as shown in FIG. .7. In this case the annular element 6 can rotate with the piston 57 whereby friction is reduced.

The pump shown in FIGS. 1 and 4 performs two suction and two pressure strokes outside and inside of the annular piston 2 at each revolution. If the liquid pumped is separately removed by suitable arrangement of the valve 33, the eifect of four pumps may be obtained. Similarly, the arrangement shown in FIG. 5 may serve as two pumps and the arrangement shown in FIG. 6 may serve as three pumps.

The rollers 7 of the pump shown in FIGURES 1 and 4 may be guided in any suitable conventional manner. Roller chains may be used as shown in FIGURES 8 and 9. In FIG. 8 the rollers 86 are provided at each end with pins 87 extending into corresponding bores of links 88 and 89. Separate pins 90 are provided for intercon-' necting the links. In FIG. 9 the pins 90 extend through suitable bores in the rollers 86.

The pumps illustrated in described may also operate as motors if fluid under pressure is supplied thereto.

By suitable interconnection of the supply and discharge conduits of two pumps a continuously variable transmission may be obtained whereby one pump acts as motor. More pumps may be interconnected in this manner for providing groups of pumps supplying operating fluid to groups of motors.

The pumps illustrated and described are not only suitable for using a liquid as operating medium but also for using a gas as operating medium whereby the pumps act as compressors and/or evacuators.

I claim:

1. A rotary piston pump comprising:

an annular rotor element having circumferentially equally spaced radial slots,

a vane device radially slidably placed in each of said slots,

an outer elastic annular element coaxially surrounding said rotor and confining a space around said rotor which space is divided by said vane devices into suction and pressure chambers,

an inner elastic annular element coaxially placed inside said rotor and confining a space adjacent to the inside of said rotor which space is divided by said vane devices into suction and pressure chambers,

means placed radially outside of said outer elastic annular element for elastically deforming said outer elastic element to change the curvature thereof and the configuration of said suction and pressure chambers,

an inlet means connected to each of said suction chambers, and

an outlet means connected to each of said pressure chambers.

2. A rotary piston pump as defined in claim 1 wherein each of said vane devices comprises an even number of rollers placed parallel to the rotation axis of the pump and adjacent to each other, the rotation axes of the rollers of each vane device being located in a radial plane of said rotor.

3. A rotary piston pump according to claim 2 wherein each of said vane devices includes slide elements slidable in the respective slot, said rollers being placed between said slide elements.

4. A rotary piston pump comprising:

a casing having a cylindrical inside wall, an annular rotor concentrically placed in said casing,

radial slots extending through said rotor and a vane device radially slidably extending through each of said slots,

a first elastic cylindrical element placed within said casing and surrounding said rotor and forming a first chamber inside said first elastic element and containing said rotor, said first elastic element forming a second chamber between said first elastic element and the interior wall of said casing, said first elastic element fluid-tightly sealing said chambers against each other,

a second elastic cylindrical element placed within said casing and inside said rotor, at least three'circumferentially equally spaced means extending inwardly from the interior wall of said casing and engaging portions of said first elastic element for pressing portions of said first elastic element toward said rotor and allowing the remaining portions of said first elastic element to form pump chambers,

each of said vane devices having an end engaging the inside of said first elastic element and having a second end engaging the outside of said second elastic element for dividing the pump chambers formed by said first elastic element into suction and pressure chambers and for shaping said second elastic element ment to correspond in shape to said first elastic element and to form pump chambers opposite the portions of the first elastic element which are pressed toward said rotor and for dividing the pump chambers formed by said second elastic element into pressure chambers and suction chambers,

an inlet means connected to each of said suction chambers, and

an outlet means connected to each of said pressure chambers.

5. A rotary piston pump as defined in claim 4 wherein said first elastic cylindrical element is formed by two concentrically placed and radially spaced annular elements and rollers placed in the space between said annular elements in parallel relation with the rotation axis of the pump.

6. A rotary piston pump according to claim 5 including link means interconnecting said rollers to form a roller chain.

7. A rotary piston pump as defined in claim 4 wherein at least one of said elastic cylindrical elements comprises at least two concentric, elastic and adjacent annular elements.

8. A rotary piston pump as defined in claim 4 wherein said means extending inwardly from the interior wall of said casing divide said second chamber into a plurality of spaces, and apertures are provided in said casing for communicating said spaces with the outside of said casing.

9. A rotary piston pump as defined in claim 4 wherein said means extending inwardly from the interior wall of said casing divide said second chamber into a plurality of separate spaces, and means are provided for individually supplying a pressure fluid to and releasing a pressure fiuid from said spaces for changing the curvature of said first elastic element and the configuration of said suction and pressure chambers.

10. A rotary piston pump as defined in claim 4 wherein each of said means extending inwardly from the interior wall of said casing includes a roller engaging the outside of said first elastic element, the axes of said rollers being parallel with the rotation axis of the pump.

11. A rotary piston pump as defined in claim 4 wherein each of said means extending inwardly from the interior wall of said casing includes a roller whose axis is parallel with the rotation axis of the pump, a shoe being provided abutting said first elastic element and being engaged by said roller.

References Cited by the Examiner UNITED STATES PATENTS 1,190,139 7/16 Ford 103-120 2,016,315 10/35 Calzoni 103-120 2,535,267 12/50 Cline 103--120 2,691,482 10/54 Ungar l03l20 2,842,064 7/58 Wahlmark 103-120 JOSEPH H. BRANSON, JR., Primary Examiner. 

1. A ROTARY PISTON PUMP COMPRISING: AN ANNULAR ROTOR ELEMENT HAVING CIRCUMFERENTIALLY EQUALLY SPACED RADIAL SLOTS, A VANE DEVICE RADIALLY SLIDABLY PLACED IN EACH OF SAID SLOTS, AN OUTER ELASTIC ANNULAR ELEMENT COAXIALLY SURROUNDING SAID ROTOR AND CONFINING A SPACE AROUND SAID ROTOR WHICH SPACE IS DIVIDED BY SAID VANE DEVICES INTO SUCTION AND PRESSURE CHAMBERS, AN INNER ELASTIC ANNULAR ELEMENT COAXIALLY PLACED INSIDE SAID ROTOR AND CONFINING A SPACE ADJACENT TO THE INSIDE OF SAID ROTOR WHICH SPACE IS DIVIDED BY SAID VANE DEVICES INTO SUCTION AND PRESSURE CHAMBERS, MEANS PLACED RADIALLY OUTSIDE OF SAID OUTER ELASTIC ANNULAR ELEMENT FOR ELASTICALLY DEFORMING SAID OUTER ELASTIC ELEMENT TO CHANGE THE CURVATURE THEREOF AND THE CONFIGURATION OF SAID SUCTION AND PRESSURE CHAMBERS, AN INLET MEANS CONNECTED TO EACH OF SAID SUCTION CHAMBERS, AND AN OUTLET MEANS CONNECTED TO EACH OF SAID PRESSURE CHAMBERS. 